History of Johnson County, Iowa, containing a history of the county, and its townships, cities and villages from 1836 to 1882, Part 64

Author: Johnson Co., Ia. History. [from old catalog]
Publication date: 1883
Publisher: Iowa City, Iowa.
Number of Pages: 980

USA > Iowa > Johnson County > History of Johnson County, Iowa, containing a history of the county, and its townships, cities and villages from 1836 to 1882 > Part 64

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On the opposite side of the river, on section 22, same township and range, rocky ledges, from thirty to forty feet in thickness, are exposed for three-quarters of a mile, with a local northerly dip, containing Spirifer euruteines. On section 15, on the left bank, there are 30 feet of regularly bedded limestone, surmounted by a bench of concretionary limestone. On section 16, one bed is charged with Terebretula reticularis, and contains also Spirifer euruteines.

All through townships 80 and 81 north, of range 6 west, of the 5th prin- cipal meridian, and as far as section 28, township 81 north, range 7 west, wherever the bluffs come up to the river, ledges of limestone of the same character and age present themselves, until they finally terminate in a rug- ged buttress of the same concretionary and brecciated mass that forms the upper part of the section at Iowa City, the coralline beds being found a few hundred yards below, at an elevation of fifty-five feet.

After passing section 28, township 81 north, range 7 west, low priarie sets in, and no rocks are visible for about twelve or fifteen miles, by the meanders of the river. On reaching a bend where the stream flows very rapidly, near where the line between sections 28 and 29 of township 81 north, range 8 west, crosses the stream from north to south, a dome- shaped mass of sandstone rests on a white sandy clay. The same kind of rock is said to be in place both on section 27 of the same township and range, and section 26, township 81 north, range 9 west of the 5th princi- pal meridian. These gritstones belong, in all probability, to the carbonif- ercus group; but no confirmative evidence was derived from organic remains.

After entering township 81 north, range 9 west, the hills recede from the river, appearing in the distance mostly as gentle swells of from seventy to one hundred feet high, presenting beautiful sites for farms, in connection with the rich adjacent bottoms. The latter afford luxuriant meadows, and the productive arable land when sufficiently elevated to be above the over- flow. On the crests of the hills are, occasionally, a few small erratics, siliceous gravel, and small angular masses of chert, but no protruding ledges in place.

Carboniferous Rocks of the Iowa River .- After leaving township 81 north, range 8 west, no rocks were seen in place near the river for about fifty miles in a direct line, and nearly double that distance by the river, which is very tortuous in its course. The deep alluvial and drift deposits effectually conceal the strata on which they rest. It is only from the angular fragments of chert occasionally seen strewn on the elevated

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HISTORY OF JOHNSON COUNTY.

ground that any clue is obtained to their age; this mineral being most prevalent in the west, through the region occupied by the carboniferous and sub-carboniferous limestones. It was not, however, until reaching the northwestern corner of Tama county, that rocks of the sub-carbonif- erous era were seen unequivocally in place. Here, on section 7 or S, town- ship 83 north, range 16 west, on the left bank of the Iowa, are bluffs of one hundred and twenty-five to one hundred and fifty feet of clevation, on the slope of which both oolitic and encrinital beds of carboniferous lime- stone protrude; and where the river crosses the corner of Marshall county, the characteristic fossil, Pentremites pyriformis, was found, along with Terebratula planosulcata, Spirifer striatus and Productus semireticulatus. Here, too, a change can be perceived in the outline of the country; in the greater elevation of the hills, in the increased growth of timber, and in the stiff, indurated, clayey subsoil.

In the southeastern part of township 84, range 15 west, on land claimed by Mr. Ballard, a thin seam of coal has been discovered, said to be about a foot thick, overlaid by shale. In consequence of the sliding of the bank, no satisfactory observations could be made, either to determine its true elevation above the river, or its thickness. From the specimens found, it appears to be of inferior quality, being much impregnated with sulphuret of iron. This is no doubt the mineral that has given rise to the reports of the existence of copper ore, on this portion of the Iowa; for, on calling on Mr. Miller, who, I was informed, had some of the copper ore in his pos- session, I was shown a sample of the same kind of pyrites.

In the detritus of the river, just above the first fork of the Iowa, frag- ments of coal are met with in the transported gravel, and below the entrance to the "Big Woods," six or seven miles above the forks, bluffs of sandstone and a highly ferruginous grit rises to the height of from one hundred and forty to one hundred and fifty feet. The latter occupies about one-third of the upper portion of the exposure, and contains from fifteen to twenty per cent. of oxide of iron, disseminated amongst a fine siliceous gravel, which, by pounding and sifting, can be separated from each other. Some portion of this ferruginous grit possesses a structure approaching to oolite. The lower part of the section is formed of con- glomerates of pebbly sandstones, together with grits, having strongly marked cross-lines of deposition. Indeed, the rocks of this part of the Iowa river assume much the character of the mill-stone grit of the north of England, which lies between the Yoredale series, and the coal-meas- ures proper.

The same formation extends for several miles along the river, rising into escarpments of sixty or seventy feet, the summits of which are crowned with pines, cedars, and other coniferœ.

Near the termination, on the right bank, where the river makes two abrupt bends, a seam of coal shows itself. It lies more after the manner of a metallic vein than a bed of coal; this arises, however, either from a dislocation, or tilting of the strata, or, more probably, from a slide, by which it appears to have been thrown nearly vertically. The confused position of the associate beds rather confirms this view. Near the coal is a bed of dark limestone, almost black when wet, containing Productus semireticulatus, Productus cora, a new species of Phillipsia, and an Eschara.

The relative order of superposition of coal, limestone, shale, and grit, is difficult to determine, by reason of the disturbance above referred to.

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HISTORY OF JOHNSON COUNTY.

The coal at present lies near the edge of the water, covered with a few feet of shale, and nearly on a level with the base of the grit escarpment, which is in sight about one or two hundred yards down stream.

For two or three miles beyond the coal-bank, the hills do not present the same abrupt appearance as they do below; soon, however, the Iowa sweeps around a great easterly bend, and again washes the base of hills of sandstones, more regularly bedded than the corresponding ranges below. The oxide of iron is here not so much disseminated through the substance of the rock, but is rather collected in bands, that fill the joints and seams of stratification.

For several miles after entering the "Big Woods," the rocks are only seen at two localities, not far apart, where a reddish-yellow limestone is exposed, a few feet above the water level, while the high ground is com- posed chiefly of 'deposits of sand and clay mixed with drift, and boulders. These are the only deposits seen for twelve or fourteen miles. About latitude 42 degrees 25 minutes, the carboniferous limestone again makes its appearance, at first in a succession of low ledges, ten or fifteen feet above the bed of the river, sometimes on one side, and sometimes on the other, until finally they form "dalles," thirty to forty feet in elevation, between the walls of which the Iowa flows, with a rapid current. The limestone which forms the base of the "dalles," is of a light flesh color, possesses an imperfect oolitic structure, and contains a small Terebratula, allied to T. laticostata. The upper third is composed of magnesian lime- stones, which have much the appearance of the magnesian limestone of the Dubuque district, but cannot belong to the same period, since they form a part of the sub-carboniferous limestone, and con-tain that form of Syringopora which M. Lesueur named Obstringolina, and which was found in that formation in Missouri. About the middle of this range of limestone, near a point known as "The Showerbath," the rocks attain their greatest elevation, dipping from t ence southerly and northerly as much as seven degrees. Numerous chalybeate springs issue from their base, depositing an abundant gelatinous hydrated oxide of iron.

These strata of carboniferous limestone continue, with little interruption, to the Falls or Rapids of the Iowa, situated in latitude 42 degrees, 32 seconds, 22 minutes. Two miles above this, the bluffs rise to the height of one hundred and thirty feet. At their base, they are composed of the semi-oolitic layers before alluded to; the coal measures proper resting on them in the following order of superposition. from above downwards:

Feet Inches

1. .. Soil and drift beds not exposed, 9 to 100

2 .. Gray argillaceous schistose limestone, .

3. . Bluish argillo-siliceous shale, 20

4. . Chert layer,

12 to 14

5. . White siliceous rock, effervescing feebly,. 4 to 5

6. . White semi-oolitic limestone, 3

A short distance beyond this section, the underlying limestone rises again toward the northwest to the height of twelve or fifteen feet, for a distance of four miles, when, at a sudden bend in the river, in latitude 42 degrees, 31 minutes, 44 seconds, before it enters and meanders through the open prairie, the limestone pitches beneath the water level, to the northwest, and is overlapped by a mass of dark, bluish gray, argillaceous shale. Here fragments of coal occur in the debris, though no regular bed seen; the slide of the argillaceous layers and vegetation may conceal

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HISTORY OF JOHNSON COUNTY.

it from view. A quarter of a mile above, the limestone is again in place, skirting the bed of the river, and continues in low walls of five to ten feet, either on one side or on the other, for four or five miles. The current of the stream becomes sluggish as it traverses low, flat land, the banks being usually only four or five feet above the river, and, these are not above five feet in elevation.

After leaving the last limestone exposure, we continued to ascend the Iowa for fifteen or twenty miles, when we finally arrived at a barren region of drift knolls stretching away as far as the eye can reach, desti- tute of timber, except a narrow belt skirting the Iowa river. The hollows below the drift knolls are wet and marshy, and the summit of the hills strewn with a thin, poor soil, that only supports a second growth of stunt- ed herbage.

The corps whose duty it was to explore, in 1848, the southern and west- ern tributaries of the St. Peter's river, observed towards the heads of the Mankato and Lesueur rivers, a country of the same character which we encountered high up on the Iowa. It was hence inferred, that these bar- ren drift knolls extend beyond the northern boundary of Iowa, covering the whole water-shed that gives rise to these streams, as well as to the Iowa and Red Cedar rivers. Seeing, therefore, no object to be attained by farther advance up the Iowa, and finding that our stores of provisions were barely sufficient to carry us back to the settlements, I determined to return after making the astronomical observations necessary to determine our position, which was found to be in latitude 42 degrees, 39 minutes, 06 seconds.

There remains to be said, in this place, only a few words with regard to the extreme branches of Red Cedar, viz .: Beaver and Otter creeks, which were explored by Mr. Macy, with a view to ascertain the precise eastern boundary of the carboniferous rocks on the Iowa river.

On account of the low, wet country bordering these streams, it was only at a few points that the rocks were visible, and these only in low ledges, near the water level, or in partial protrusions from under the mass of drift in the higher ground.

Mr. Macy succeeded, however. in detecting, in a ridge about five miles north of Otter creek, a flesh-colored limestone, containing that variety of Leptaena depressa of Dalman, which occurs in the corniferous limestone of New York, and is known there under the name Strophomena undula- tus. At a higher level in the same ridge a buff-colored magnesian lime- stone was observed, in which no fossils were discovered, but which pos- sesses the lithological character of the dolomitic beds of the carboniferous limestones found near the Iowa, a few miles below the rapids, near lati- tude 42 degrees, 30 minutes. Thus, the dividing ridge between the head waters of the extreme western branches of the Red Cedar river (Otter Creek and Elk Fork), is probably the boundary between the limestones of the Devonian and Carboniferous Eras."

PROF. AGASSIZ AT IOWA CITY.

During the summer of 1866, the eminent professor of Zoology in Har- . vard University, Prof. Louis Agassiz, made a visit to Iowa City, and here for the first time in his life saw coral beds of the Devonian age of geology. (See geological chart on page 547.) This circumstance rendered the event of his visit here one of note and interest to the whole scientific world, and

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HISTORY OF JOHNSON COUNTY.

permanently fixed Iowa city in the directories of science as one of the marked localities where rare and important fossil specimens could readily be collected. Mrs. Agassiz, who was a lady of fine culture, a sci- entist herself, and yet a plain-hearted, motherly woman, was with her husband on this occasion; in fact he rarely went anywhere without her. They came to Iowa City as guests of Prof. T. S. Parvin; and Newton Parvin, who was then a mere lad, remembers how they all went out fossil- gathering. The first place they came to, where many specimens were found was just where the filter chamber of the city waterworks is now built, at the upper end of Madison street. Here Prof. Agassiz ran about just like a little boy under a windfall apple tree, picking up everything he saw that had fossil marks on it; and when he had collected a pile as big as a half-bushel measure, he called out, " Here, mother, we must take all these home with us." Prof Parvin laughed, and said, "O, we'll find plenty of nicer ones than those." The party went on for a mile or two along the river bank, and among the stone quarries; and Agassiz was so delighted and enthusiastic about the rich finds of fossils that every time they stopped he would hurry around and gather a new pile of speci- mens, and say, "Now, mother, we must take all these home." All of his piles would have made a lumber wagon load; but he was gratified by the choicest specimens being picked out and carried along for further study.

That same evening he delivered a lecture on the very matters over which he had been so much elated during the day; and in regard to this historic event we quote the report published in the State Press at the time, as follows:

PROF. AGASSIZ AND HIS LECTURE.

On Wednesday evening last the people of Iowa City were afforded the rare opportunity of hearing that profound student of science and cele- brated naturalist, Professor Agassiz. At an early hour the University chapel was filled with an intelligent and appreciative audience. After vocal music by a choir composed of young ladies and gentlemen, students of the University, the lecturer was introduced by Dr. O. M. Spencer. He surprised the greater portion of the audience by announcing the subject of the lecture to be "The Coral Reefs of Iowa City," most persons hav- ing associated coral with the sea, and never thought that the earth on which we now dwell was once, during the infinity of the past, submerged by the waters.

The lecturer at once proceeded to his subject with the familiarity of manner as though he were about to instruct a class. His lecture through- out was illustrated by the use of the blackboard. He said it had afforded him much pleasure to have the opportunity of visiting this locality and observing for himself the coral formations of which he had heard in the east; and fully satisfying himself with regard to the geological character of this country. He explained the process of coral growth by reference to the reefs on the coast of Florida, fully described the structure and functions of the coral animal, and explained the manner in which these little creatures extract the calcareous portion of the sea-water; how the

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HISTORY OF JOHNSON COUNTY.

new polyps appear in the form of a bud on the side of the first individual, and how their additions continue to be made until twelve millions of them have been known to exist in a single cluster. Coral is the strong frame which belongs to these animals as a skeleton belongs to individuals of the higher orders of animals, being formed by the involuntary secretion of cal- careous matter. He explained how the great coral reefs were formed by the successive growth of Astreas, Madrepores, Meandrinas, etc., and their solidification, in process of time, occasioned by the constantly increas- ing pressure, into a substance differing in no essential particular from the strata of limestone spread over the western states, as well as the other different characteristics that are impressed on these formations by the different conditions in which they exist depending on temperature and pressure.

The American continent, instead of being the "new world," was really much older than any part of the eastern hemisphere, an original continen- tal form having appeared much earlier along the line of the great lakes, extending east and west, and with this as a basis, the coral animals had for ages lived, died, and solidified until this gradual process had formed the vast continent on which we live. The next projection above the water was the Alleghany mountains, extending through the eastern portion of the continent. Here, in the vicinity of our city, the evi- dence of coal formation were found in perfection. We do not pretend to give even an outline of the lecture, but merely to indicate to our read- ers something of the course pursued in the treatment of this, to most of us, very novel subject. The lecturer cannot be said to be eloquent, his oratory being altogether of the conversational and instructive style. That he is a profound master of natural sciences there can be no doubt, and has the peculiar faculty of making everything so plain that all who hear him wonder that they had not known the same things long ago, and that they were not capable of elucidating them as well as the distinguished scholar to whom they listened.

After the lecture, Prof. Agassiz was handsomely entertained by Prof. T. S. Parvin at his residence, where the facutly of the University, and a few invited guests, had an opportunity to become personally acquainted with him, and to learn something of the true power of his mind from private conversation.

On Thursday morning he delivered a lecture on the subject of the " Glaciers" to the students and faculty of the University, in which his vast knowledge of the transformations and changes the earth has under- gone, was fully displayed. He described the process by which ice is formed, and explained the difference in the formation of ice from water and from snow-described the immense glaciers he has examined in Europe, one of which he had measured with a line to the deapth of 1,000 feet-explained the causes by which these immense masses of ice are put in motion, and the effects produced upon the 'country over which they move. He said that the evidences of a " glacier " having passed over any portion of the earth's surface were palpable to every geologist, and as easily distinguished as a silver coin is distinguished from a copper penny. These indications are the deposits of "drifts," or loose stones upon the surface, and the polished appearence of the stones and rocks. All parts of Europe bear evidences of having at one time been under immense loads of moving ice, and the lecturer accounted for the boulders and smooth

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HISTORY OF JOHNSON COUNTY.

stones that are scattered over our prairies on the hypothesis that immense iceburgs had once moved down from the north over the country.

FOSSILS OF JOHNSON COUNTY.

The Department of Natural Science in the State University, which is in charge of Prof. Calvin, is well supplied with representative fossils of the different geological lages, from all parts of Iowa and many of the more important fossil beds of the United States, and some foreign countries. Iowa City has not only a national but a world-wide name in scientific cir- cles, from the fact that Prof. Agassiz here first saw fossil corals of the Devonian age in situ-that is, undisturbed, lying in their place and posi- tion just as they grew, during that far remote period of geological time; [see geological chart on page 547]; and also from the fact that specimens of rare interest to students of paleontology are so easily obtained here. Prof. Calvin's collection is of course especially rich and full in specimens from the fossil beds of Johnson county; and he has very kindly furnished, for this work, a complete list of them, which has not before been pub- lished anywhere. There are now known to be at least twenty species of Iowa fossils unpublished-some of them entirely new to science; and doubtless many more will be discovered, for Iowa has as yet done less for geological science than even Minnesota, Missouri, or Kansas. All of her geological surveys have been cramped, and stinted, and hurried, from lack of funds.

FOSSILS OF JOHNSON COUNTY.

LIST PREPARED BY

PROF. SAMUEL CALVIN, A. M.,

PROFESSOR OF NATURAL SCIENCE IN THE IOWA STATE UNIVERSITY.

With the exception of a few species of coal plants found in the small outlier of carboniferous sandstone near Terrill's Mill, the fossils of Johnson county are largely the common species that characterize the Devon- ian limestones everywhere in the west.

The following Devonian species have been recognized:

CLASS, PROTOZOA .- ORDER, SPONGIDA. (Fossil Sponges.)

Astreaspongia hamiltonensis, Meek and Worthen.

Idiostroma gordiaceum, Winchell. Cænostroma pustulifera, Winchell. Cænostroma monticulifera, Winchell.

Cænostroma (undescribed species.) Stromatopora polymorpha* (?) and other species.

*Stromatopra grew in a body of layers like a pile of inverted dishes, commencing with a very small one in the center at the bottom and gradually increasing upward and outward. Cænostroma pustulifera is compossed of layers dotted with little pustule-like elevations on

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HISTORY OF JOHNSON COUNTY.

CLASS, CŒLENTERATA .- ORDER, RUGOSA.

Acervularia davidsoni, Edwards & Haime.

Acervularia profunda, Hall.

Phillipsastrea gigas,* Owen. Diphyphyllum archiaci, Billings. Cyathophyllum, robustum, Hall.

Cystiphyllum americanum, Edwards and Haime.

Cystiphyllum conifollis, Hall.

Chonophyllum magnificum, Rominger(?)

Cyathophyllum+ (undescribed species).

Aulocophyllum sulcatum, Edwards and Haime.

ORDER TABULATA.

Favosites # emmonsi, Rominger.

Favosites hamiltonensis, Rom.

Favosites hemispherica, Yandell & Shumard, Var.

Favosites limitaris, Rom.

Favosites digitatus, Rom. Favosites placenta, Rom.

Alveolites goldfussi, Billings.

Striatopora iowensis, Owen.

Striatopora rugosa, Hall. Syringopora nobilis, Billings.

Aulopora (two or three species.)

Monticulipora monticola, White.

CLASS, ECHINODERMATA-ORDER, CRINOIDEA .*

Strobilocystites calvini, White. Strobilocystites polleyi, (new species), Calvin. Nucleocrinus angularis, Lyon. Nucleocrinus, (new species).

one side and a corresponding pit on the other side where the pustule on the next layer below fitted up into it. ' C. monteculifera is what the Iowa City marble cutters call "wave;" its wavy lines look somewhat lixe an outline map of a range of monticles, or hillocks- hence the scientific name given to it .- H. A. R.

*The different species of Acervularia and Phillipsastrea are what the marble workers and people of Iowa City eall "birds-eye" marble .- H. A. R.

+ Some varieties of Cyathophyllum are calyx-shaped, or cup-like, having a depression in the large end and then tapering to a point like a horn tip, and usually somewhat curvedi They have been called and believed to be petrified buffalo calf's horns, by unlearned people .-- H. A. R.

# The different species of Favosites form the kind of stone commonly called "fish egg" marble; but it is an entirely different product from the true fish-egg or oolite marble, which is not found here at all. Favosites means "honey comb stone," and all of those specimens which look like petrified honey comb belong to this genus .- H. A. R.

** The erinoids grew on a jointed stem, which had roots like a plant in the sea bottom mud, and supported a head with arms that grew out from the common center and turned up; these arms bore a fringe of vibratile cilia, which makes a well preserved fossil speci- men look like one side of a quill feather. The stem shows an annulated or ring joint structure which leads to their being often called petrified worms. But they belong to that great group of radiate animals which includes also the star fishes .---- H. A. R.

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History of Johnson County, Iowa, containing a history of the county, and its townships, cities and villages from 1836 to 1882, Part 64

Author: Johnson Co., Ia. History. [from old catalog] Publication date: 1883 Publisher: Iowa City, Iowa. Number of Pages: 980

Author: Johnson Co., Ia. History. [from old catalog]
Publication date: 1883
Publisher: Iowa City, Iowa.
Number of Pages: 980